1. Field of the Invention
This invention relates to the field of amplifiably processing signals read from encoded credit cards and more particularly to card speed compensating circuits incorporated into credit card reader amplifiers.
2. Prior Art
Previous mechanisms having to do with credit card reader amplifiers were not able to accurately identify encoded data on a magnetic stripe on a credit card when the card was passed through a reading device at a speed greater or less than the normal speed that the amplifier was designed for. As a result, when cards were read at a non-normal speed, data pulses might either be lost entirely or confused with clock pulses also derived from the stripe thus producing an unreliable condition as to what was data.
Another problem associated with such amplifier mechanisms concerns itself with noisy transients picked up by the reader during normal operation and how to distinguish data and clock pulses from such transients.
An additional problem concerns itself with the sensing of the real start position for reading of the card's stripe. Because of repeated use or faulty manufacture, the normal begin read area on the stripe of the card may be damaged causing a delay in locking in on a clock pulse resulting in loss of data during the interval.